Digital graphic equalizer

Abstract

A digital graphic equalizer for obtaining a boost characteristic and an attenuation characteristic using band pass filters, each constituted by a digital filter, and an adder. For a boost characteristic, an input signal is supplied to first band pass filters and resultant filtered signals and the input signal are added by a first adder. For an attenuation characteristic, the output signal of a second adder is fed back to second band pass filters and resultant filtered signals and the input signal are added by a second adder.

What is claimed is: 
     
       1. A digital graphic equalizer for obtaining a boost characteristic and an attenuation characteristic using a digital signal processor which realizes band pass filters, each constituted by a digital filter, and adding means, said equalizer comprising: first band pass filters for receiving an input signal to obtain first filtered signals in a boost mode;   first adding means for adding said first filtered signals and said input signal to obtain a boost output signal in said boost mode;   second band pass filters for receiving an attenuation output signal to obtain second filtered signals in a attenuation mode; and   second adding means for adding said second filtered signals and said input signal to obtain said attenuation output signal in said attenuation mode.   
     
     
       2. The digital graphic equalizer according to claim 1, further comprising delay means realized in said digital signal processor, for delaying a signal to be fed from said second adding means to said second band pass filters in said attenuation mode.